Fabric for humidification of air and method of making



Patented June 23, 1936 FABRIC FORHUMIDIFICATION OF AIR Q METHOD OF MAKING Lawrence L. Heffner, Baltimore, Md., assignor to Wm. E.

Hooper & Sons Company, Baltimore,

Md.. a corporation of Maryland No Drawing. Application March 9, 1934,

Serial No. 714,841

9 Claims.

The invention relates to air conditioning particularly to humidifying and cooling by evaporationof the air in a room or apartment for human occupation. This is accomplished by passing an air draft in contact with a fabric which is continuously saturated or moistened with water or other liquid with which the air is to be treated.

There are included in the prior art various patents'showing evaporators of this general nature. comprising fabric sheets or screens which are placed in an air draft and supplied with liquid which flows downwardly by gravity over the cloth, and is thus distributed to the air by evaporation, but these devices involve various expedients for distributing the liquid to the fabric which are more or less complicated and variable in'their operation requiring exact and frequent adjustment so that they are not generally acceptable, and further their manufacture involves considerable expense so that they are not adapted for distribution at a low price which would make them generally available. Certain of the prior patents also suggest the use of a fabric wick led upwardly from a, receptacle containing water and disposed upon a frame placed in the draft of a fan but this apparatus has never been practical because the fabrics which have been available for this purpose are not sufllciently hygroscopic and do not have sufficient capillary attraction to draw the water or other liquid used for this purpose upwardly for a sufiicient distance or in suilicient quantities to distribute it in thefan draft in such a way as to make it eiiective in air conditioning. I

The present invention relates to a fabric which is particularly adapted to this purpose and capable of conducting water or other liquid to be evaporated in air conditioning upwardly from a receptacle so that it is distributed upon a screen composed of the same fabric which is located in a fan or similar draft to distribute the liquid to the atmosphere, thereby effecting humidification and cooling, in the conditioning of air for use in rooms and apartments for human habitation or for other purposes as previously outlined. v The fabric of the invention has been tested in practice, being placed with its lower end in a receptacle containing water. and extending upwardly from the receptacle for a distance of 2 to 3 feet, the upper portion of the fabric, which was spread out to a width of about 6 inches, being located in an air draft created by a fan, maintaining its moisture at all times by conduction of the liquid from below and evaporates approximately one liter of water an hour, the fan being of approximately a foot in diameter and operated at a speed of 900 R. P. M. I

The invention relates'to the fabric as treated to increase its hygroscopic qualities and its capillarity'orit's ability to conduct water and other liquids upwardly from a receptacle or other means for wetting the fabric at the bottom, andthe invention also relates'to the method of treating the fabric for this purpose.

In, accordance with the invention, the fabric which is of cotton of any suitable weave, as wicking, duck or a loose simple weave or cheese cloth or the like, is first treated with a solution of caustic soda, otherwise known as sodium hydroxide. This solution may be of any suitable strength, a 10 to 25% solution having been used with satisfactory results. The fabric is boiled in the solution'for a. period which is according to the present practice of the invention not less than an hour and which may be any suitable time which is not suflicient to dissolve the fibers, the

object of this first step of the process being to remove from the fibers the natural oils and waxes, and while the practice 'of the invention so far relates mainly to the treatment of woven fabric, the invention also contemplates treatment of the yarn if preferred before weaving.

, The material may, if desired, be treated at temperatures below boiling or under pressure, which tends to prevent boiling, and other solvents,

as potassium hydroxide and various organic solvents made from wood, coal, tar or petroleum distillates may be used, sodium hydroxide being however the preferred solvent within the broa conception of the invention.

After a suitable period has elapsed, the material is removed from the alkaline solution described and washed and neutralized with a weak acid solution, almost any acid being available for this purpose, acetic acid having been used to advantage. The amount applied should be onlysuflicient to neutralize any alkali which is not actually removed from the fabric. The fabric is then immersed in a water solution of a salt of the rare earth metals. This solution has to advantage been made of ten per cent. strength and the best result has been obtained with the chlorides of, the rare earth metals, the material 7 rare earth metal chlorides. The rare earth metal acetates and carbonates are also found to be available for this purpose, though not quite as effective as chlorides.

The solution is best applied at a temperature of from 90 to 100 degrees F. and the treatment being obtained commercially under the-name of 7 moved from the solution and treated with heat, or

it may be termed baked", producing a fabric which is thoroughly impregnated with the rare earth chlorides to the degree indicated, the material being deposited throughout the fabric and within the fibers which have been thoroughly soaked with the solution.

This fabric is found to be more highly efllcient in conducting water by absorption or capillarity than any formerly known fabric which has been cited. It leads the water upwardly from a receptacle or other point of application for a distance of from two or three feet as shown by experiment. This distance is sufficient for the purposes in hand, and conduction takes place at a suflicient speed so that a narrow section of the fabric as described has been found to release in a fan draft a quantity of water amounting to one liter per hour, which is thus evaporated and distributed through the room. The area of fabric which has been at present utilized in this way in supplying moisture to a fan draft is small and the quantity of water can therefore be widely and proportionately increased by increasing the cross sectional area of the material used for conduction and the area of the material spread in the fan draft. It is also found that liquids other than water are even more efliciently conducted in this way and that in their evaporation liquids which can be produced at a sufilciently low cost to make them available for this purpose give a drop in temperature of several degrees more than is obtainable by water and have a beneficial effect on the atmosphere so that air conditioning is made possible by means of a simple inexpensive fan in place of the elaborate apparatus now in use. The cooling and moistening effect which is obtained in this way is entirely satisfactory for the purpose in hand and air conditioning in satisfactory form is thus made generally available.

It is also of interest that some of the salts of the rare earth metals which are employed in this way are to a notable degree radio active and that many of them have the eifect of killing the bacteria in the moisture which is distributed and also of preventing mildew and deterioration of the fabric.

I have thus described specifically and in detail a fabric for use in conducting water and other liquids in the conditioning of air by evaporation and the method of making the same, the specification being descriptive and in detail, in order that the manner of constructing, operating and applying the invention may be fully understood, however, the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in the claims.

What I claim as new and desire to secure by Letters Patent is:

1. A fabric for use in the absorption and conduction of moisture by leading the moisture upward from a point of application to a point of distribution, to an air draft at a higher level than the point of application, which draft contacts the surface of the fabric, the fabric comprising cotton and having the natural oils and waxes removed, the material being impregnated with salts of the rare earth metals.

2. A fabric for use in the absorption and confrom a point of application to a point of distribution toj the air, the fabric consisting of cotcotton and having the natural oils and waxes removed, the material being impregnated with salts of the rare earth metals which take the place of 5 the oils and waxes.

3. A fabric for use in the absorption and conduction of moisture to lead the moisture upward from a point of application to a point of distribution to the air, the fabric consisting of cot- 10 ton and having the natural oils and waxes removed, the material being impregnated with the chlorides of the rare earth metals which take the place of the oils and waxes.

4. The method of treating cotton fabric for use 1 in air conditioning to render it hygroscopic and increase its ability to conduct moisture and give it the property of conducting moisture upwardly from a point of application to a point of distribution to the air which method consists in treating the fabric in a caustic solution to an extent suflicient to remove the natural oils and waxes without breaking down the cellulose material composing the fiber and them impregnating it with a solution of the salts of the rare earth metals and drying it substantially as described.

5. The method of treating cotton fabric or the like to increase its hygroscopic properties and to give it the property of conducting water upwardly to a point of distribution for purposes of humidification which consists in boiling the material in a solution of caustic soda for a period which is sufllcient to remove the natural oils and waxes, but not sufficient to so break down the cellulose structure of the fiber, then removing the material from the alkaline solution, washing and neutrallizing with an acid any of the caustic which may remain in the material, then immersing the material in a solution of a chloride of the rare earth metals for a period sufficient to effect complete saturation of the material with said solution, removing it from the solution and baking. a

6. The method of treating cotton for use in conditioning of air to render the material more hygroscopicand increase its ability to conduct liquid which consists in treating it in an alkaline solution at a high temperature to remove the natural oils and greases without dissolving the fiber, then treating to eliminate the alkali, saturating it with a water solution of rare earth salts and drying it to solidify the salt.

7. The method of treating cotton for use in the conditioning of air to render the material more hygroscopic and increase its ability to conduct liquid which consists in washing it with an alkaline solution at a high temperature to remove the natural oils and greases without dissolving the fiber, then washing to eliminate the alkali, impregnating it with a solution of the rare earth chlorides and further treating it to solidify the chlorides.

8, A fabric for use in the manner described, the same consisting of a cotton fiber from which the waxes and oils have been removed and which is fully impregnated with a rare earth metal chloride.

9. A fabric for use as a conductor of liquid the same comprising cotton fiber from which the waxes and oils have been removed and which is fully impregnated with the salts of the rare earth metals substantially as described.

LAWRENCE L. HEFFNER. 

